Trump's ex-national security advisor wants to restart US nuke testing. Nuclear experts warn that's not a good idea.

• A former Trump advisor says a second Trump term should involve restarting nuclear testing.
• Nuclear experts pushed back on the idea, warning that it'll lead to a global arms race, among other problems.
• Nuke testing could prompt Russia and China into nuclear competition.

Donald Trump's former White House national security advisor is arguing that a second term in office should involve restarting US nuclear testing for the first time in over 30 years.